public class Test {
    public static void func(Animal animal) {
        animal.eat();
        animal.age = 3;
    }
    public static Animal func2() {
        return  new Dog("旺旺",1,"黑色");
    }
    public static void main(String[] args) {
        Animal animal = new Dog("1",1,"1");
        animal.eat();
        Dog dog = (Dog)animal;
    }
}
